Valvular heart diseases include mitral valve prolapse in which a leaflet of the mitral valve is displaced into the left atrium during the systolic phase of a cardiac cycle. Mitral valve prolapse can lead to mitral regurgitation in which the mitral valve does not close properly during the systolic phase, causing abnormal leaking of blood from the left ventricle, through the mitral valve and into the left atrium.
Valvular heart diseases also include mitral stenosis in which the orifice of the mitral valve is abnormally narrowed, thus impeding blood flow into the left ventricle. Similarly, tricuspid stenosis can impede blood flow into the right ventricle. Some patients may be affected by a combination of mitral/tricuspid stenosis and mitral/tricuspid valve regurgitation, while others may be affected by either one or the other. Serious valvular heart diseases may be treated by replacing or repairing the defective heart valve in an open heart surgical procedure in which a patient's defective heart valve is manually or robotically replaced with a different valve. The open heart surgical replacement procedure requires placing the patient on cardiopulmonary bypass to stop blood flow through the heart when the heart is opened up.